Chemokines are chemotactic cytokines, of molecular weight 6-15 kDa, that are released by a wide variety of cells to attract and activate, among other cell types, macrophages, T and B lymphocytes, eosinophils, basophils and neutrophils (reviewed in: Luster, New Eng. J. Med. 1998, 338, 436-445 and Rollins, Blood 1997, 90, 909-928). There are two major classes of chemokines, CXC and CC, depending on whether the first two cysteines in the amino acid sequence are separated by a single amino acid (CXC) or are adjacent (CC). The CXC chemokines, such as interleukin-8 (IL-8), neutrophil-activating protein-2 (NAP-2) and melanoma growth stimulatory activity protein (MGSA) are chemotactic primarily for neutrophils and T lymphocytes, whereas the CC chemokines, such as RANTES, MIP-1α, MIP-1β, the monocyte chemotactic proteins (MCP-1, MCP-2, MCP-3, MCP-4, and MCP-5) and the eotaxins (-1 and -2) are chemotactic for, among other cell types, macrophages, T lymphocytes, eosinophils, dendritic cells, and basophils. There also exist the chemokines lymphotactin-1, lymphotactin-2 (both C chemokines), and fractalkine (a CXXXC chemokine) that do not fall into either of the major chemokine subfamilies.
The chemokines bind to specific cell-surface receptors belonging to the family of G-protein-coupled seven-transmembrane-domain proteins (reviewed in: Horuk, Trends Pharm. Sci. 1994, 15, 159-165) which are termed “chemokine receptors.” On binding their cognate ligands, chemokine receptors transduce an intracellular signal though the associated trimeric G proteins, resulting in, among other responses, a rapid increase in intracellular calcium concentration, changes in cell shape, increased expression of cellular adhesion molecules, degranulation, and promotion of cell migration. There are at least ten human chemokine receptors that bind or respond to CC chemokines with the following characteristic patterns: CCR-1 (or “CKR-1” or “CC-CKR-1”) [MIP-1α, MCP-3, MCP-4, RANTES] (Ben-Barruch, et al., Cell 1993, 72, 415-425, and Luster, New Eng. J. Med. 1998, 338, 436-445); CCR-2A and CCR-2B (or “CKR-2A”/“CKR-2B” or “CC-CKR-2A”/“CC-CKR-2B”) [MCP-1, MCP-2, MCP-3, MCP-4, MCP-5] (Charo, et al., Proc. Natl. Acad. Sci. USA 1994, 91, 2752-2756, and Luster, New Eng. J. Med. 1998, 338, 436-445); CCR-3 (or “CKR-3” or “CC-CKR-3”) [eotaxin-1, eotaxin-2, RANTES, MCP-3, MCP-4] (Combadiere, et al., J. Biol. Chem. 1995, 270, 16491-16494, and Luster, New Eng. J. Med. 1998, 338, 436-445); CCR-4 (or “CKR-4” or “CC-CKR-4”) [TARC, MIP-1α, RANTES, MCP-1] (Power, et al., J. Biol. Chem. 1995, 270, 19495-19500, and Luster, New Eng. J. Med. 1998, 338, 436-445); CCR-5 (or “CKR-5” OR “CC-CKR-5”) [MIP-1α, RANTES, MIP-1β] (Sanson, et al., Biochemistry 1996, 35, 3362-3367); CCR-6 (or “CKR-6” or “CC-CKR-6”) [LARC] (Baba, et al., J. Biol. Chem. 1997, 272, 14893-14898); CCR-7 (or “CKR-7” or “CC-CKR-7”) [ELC] (Yoshie et al., J. Leukoc. Biol. 1997, 62, 634-644); CCR-8 (or “CKR-8” or “CC-CKR-8”) [I-309, TARC, MIP-1β] (Napolitano et al., J. Immunol., 1996, 157, 2759-2763, and Bernardini, et al., Eur. J. Immunol. 1998, 28, 582-588); CCR-10 (or “CKR-10” or “CC-CKR-10”) [MCP-1, MCP-3] (Bonini, et al., DNA and Cell Biol. 1997, 16, 1249-1256); and CCR-11 [MCP-1, MCP-2, and MCP-4] (Schweickert, et al., J. Biol. Chem. 2000, 275, 90550).
In addition to the mammalian chemokine receptors, mammalian cytomegaloviruses, herpesviruses and poxviruses have been shown to express, in infected cells, proteins with the binding properties of chemokine receptors (reviewed in: Wells and Schwartz, Curr. Opin. Biotech. 1997, 8, 741-748). Human CC chemokines, such as RANTES and MCP-3, can cause rapid mobilization of calcium via these virally encoded receptors. Receptor expression may be permissive for infection by allowing for the subversion of normal immune system surveillance and response to infection. Additionally, human chemokine receptors, such as CXCR4, CCR2, CCR3, CCR5 and CCR8, can act as co-receptors for the infection of mammalian cells by microbes as with, for example, the human immunodeficiency viruses (HIV).
The chemokines and their cognate receptors have been implicated as being important mediators of inflammatory, infectious, and immunoregulatory disorders and diseases, including asthma and allergic diseases, as well as autoimmune pathologies such as rheumatoid arthritis and atherosclerosis (reviewed in: Bharat K. Trivedi, et al, Ann. Reports Med. Chem. 2000, 35, 191; John Saunders and Christine M. Tarby, Drug Disc. Today 1999, 4, 80; Brett A. Premack and Thomas J. Schall, Nature Medicine 1996, 2, 1174). For example, the chemokine monocyte chemoattractant-1 (MCP-1) and its receptor CC Chekmokine Receptor 2 (CCR-2) play a pivotal role in attracting leukocytes to sites of inflammation and in subsequently activating these cells. When the chemokine MCP-1 binds to CCR-2, it induces a rapid increase in intracellular calcium concentration, increased expression of cellular adhesion molecules, cellular degranulation, and the promotion of leukocyte migration. Demonstration of the importance of the MCP-1/CCR-2 interaction has been provided by experiments with genetically modified mice. MCP-1 −/− mice had normal numbers of leukocytes and macrophages, but were unable to recruit monocytes into sites of inflammation after several different types of immune challenge (Bao Lu, et al., J. Exp. Med. 1998, 187, 601). Likewise, CCR-2 −/− mice were unable to recruit monocytes or produce interferon-γ when challenged with various exogenous agents; moreover, the leukocytes of CCR-2 null mice did not migrate in response to MCP-1 (Landin Boring, et al., J. Clin. Invest. 1997, 100, 2552), thereby demonstrating the specificity of the MCP-1/CCR-2 interaction. Two other groups have independently reported equivalent results with different strains of CCR-2 −/− mice (William A. Kuziel, et al., Proc. Natl. Acad. Sci. USA 1997, 94, 12053, and Takao Kurihara, et al., J. Exp. Med. 1997, 186, 1757). The viability and generally normal health of the MCP-1 −/− and CCR-2 −/− animals is noteworthy, in that disruption of the MCP-1/CCR-2 interaction does not induce physiological crisis. Taken together, these data lead one to the conclusion that molecules that block the actions of MCP-1 would be useful in treating a number of inflammatory and autoimmune disorders. This hypothesis has now been validated in a number of different animal disease models, as described below.
Several studies have demonstrated the potential therapeutic value of antagonism of the MCP-1/CCR2 interaction in treating rheumatoid arthritis. A DNA vaccine encoding MCP-1 was shown recently to ameliorate chronic polyadjuvant-induced arthritis in rats (Sawsan Youssef, et al., J. Clin. Invest. 2000, 106, 361). Likewise, inflammatory disease symptoms could be controlled via direct administration of antibodies for MCP-1 to rats with collagen-induced arthritis (Hiroomi Ogata, et al., J. Pathol. 1997, 182, 106), or streptococcal cell wall-induced arthritis (Ralph C. Schimmer, et al., J. Immunol. 1998, 160, 1466). Perhaps most significantly, a peptide antagonist of MCP-1, MCP-1(9-76), was shown both to prevent disease onset and to reduce disease symptoms (depending on the time of administration) in the MRL-1pr mouse model of arthritis (Jiang-Hong Gong, et al., J. Exp. Med. 1997, 186, 131).
Three key studies have demonstrated the potential therapeutic value of antagonism of the MCP-1/CCR2 interaction in treating atherosclerosis. For example, when MCP-1 −/− mice are mated with LDL receptor-deficient mice, an 83% reduction in aortic lipid deposition was observed (Long Gu, et al., Mol. Cell 1998, 2, 275). Similarly, when MCP-1 was genetically ablated from mice which already overexpressed human apolipoprotein B, the resulting mice were protected from atherosclerotic lesion formation relative to the MCP-1 +/+ apoB control mice (Jennifa Gosling, et al., J. Clin. Invest. 1999, 103, 773). Likewise, when CCR-2 −/− mice are crossed with apolipoprotein E mice, a significant decrease in the incidence of atherosclerotic lesions was observed (Landin Boring, et al, Nature 1998, 394, 894).
Other studies have demonstrated the potential therapeutic value of antagonism of the MCP-1/CCR-2 interaction in treating multiple sclerosis; all of these studies have been demonstrated in experimental autoimmune encephalomyelitis (EAE), the standard animal model for multiple scelerosis. Administration of antibodies for MCP-1 to animals with EAE significantly diminished disease relapse (K. J. Kennedy, et al., J. Neuroimmunol. 1998, 92, 98). Furthermore, two recent reports have now shown that CCR-2 −/− mice are resistant to EAE (Brian T. Fife, et al., J. Exp. Med. 2000, 192, 899; Leonid Izikson, et al., J. Exp. Med. 2000, 192, 1075).
Other studies have demonstrated the potential therapeutic value of antagonism of the MCP-1/CCR2 interaction in treating asthma. Sequestration of MCP-1 with a neutralizing antibody in ovalbumin-challenged mice resulted in marked decrease in bronchial hyperresponsiveness and inflammation (Jose-Angel Gonzalo, et al., J. Exp. Med. 1998, 188, 157). It proved possible to reduce allergic airway inflammation in Schistosoma mansoni egg-challenged mice through the administration of antibodies for MCP-1 (Nicholas W. Lukacs, et al., J. Immunol. 1997, 158, 4398). Consistent with this, MCP-1 −/− mice displayed a reduced response to challenge with Schistosoma mansoni egg (Bao Lu, et al., J. Exp. Med. 1998, 187, 601).
Other studies have demonstrated the potential therapeutic value of antagonism of the MCP-1/CCR2 interaction in treating kidney disease. Administration of antibodies for MCP-1 in a murine model of glomerularnephritis resulted in a marked decrease in glomerular crescent formation and deposition of type I collagen (Clare M. Lloyd, et al., J. Exp. Med. 1997, 185, 1371). In addition, MCP-1 −/− mice with induced nephrotoxic serum nephritis showed significantly less tubular damage than their MCP-1 +/+ counterparts (Gregory H. Tesch, et al., J. Clin. Invest. 1999, 103, 73).
One study has demonstrated the potential therapeutic value of antagonism of the MCP-1/CCR2 interaction in treating systemic lupus erythematosus. Crossing of MCP-1 −/− mice with MRL-FAS1Pr mice—the latter of which have a fatal autoimmune disease that is analogous to human systemic lupus erythematosus—results mice that have less disease and longer survival than the wildtype MRL-FAS1pr mice (Gregory H. Tesch, et al., J. Exp. Med. 1999, 190, 1813).
One study has demonstrated the potential therapeutic value of antagonism of the MCP-1/CCR2 interaction in treating colitis. CCR-2 −/− mice were protected from the effects of dextran sodium sulfate-induced colitis (Pietro G. Andres, et al., J. Immunol. 2000, 164, 6303).
One study has demonstrated the potential therapeutic value of antagonism of the MCP-1/CCR2 interaction in treating alveolitis. When rats with IgA immune complex lung injury were treated intravenously with antibodies raised against rat MCP-1 (JE), the symptoms of alveolitis were partially aleviated (Michael L. Jones, et al., J. Immunol. 1992, 149, 2147).
Other studies have provided evidence that MCP-1 is overexpressed in various disease states not mentioned above. These reports provide strong correlative evidence that MCP-1 antagonists could be useful therapeutics for such diseases. Two reports described the overexpression of MCP-1 in the intestinal epithelial cells and bowel mucosa of patients with inflammatory bowel disease (H. C. Reinecker, et al., Gastroenterology 1995, 108, 40, and Michael C. Grimm, et al., J. Leukoc. Biol. 1996, 59, 804). Two reports describe the overexpression of MCP-1 rats with induced brain trauma (J. S. King, et al., J. Neuroimmunol. 1994, 56, 127, and Joan W. Berman, et al., J. Immunol. 1996, 156, 3017). Another study has demonstrated the overexpression of MCP-1 in rodent cardiac allografts, suggesting a role for MCP-1 in the pathogenesis of transplant arteriosclerosis(Mary E. Russell, et al. Proc. Natl. Acad. Sci. USA 1993, 90, 6086). The overexpression of MCP-1 has been noted in the lung endothelial cells of patients with idiopathic pulmonary fibrosis (Harry N. Antoniades, et al., Proc. Natl. Acad. Sci. USA 1992, 89, 5371). Similarly, the overexpression of MCP-1 has been noted in the skin from patients with psoriasis (M. Deleuran, et al., J. Dermatol. Sci. 1996, 13, 228, and R. Gillitzer, et al., J. Invest. Dermatol. 1993, 101, 127). Finally, a recent report has shown that MCP-1 is overexpressed in the brains and cerebrospinal fluid of patients with HIV-1-associated dementia (Alfredo Garzino-Demo, WO 99/46991).
It should also be noted that CCR-2 has been implicated as a co-receptor for some strains of HIV (B. J. Doranz, et al., Cell 1996, 85, 1149). It has also been determined that the use of CCR-2 as an HIV co-receptor can be correlated with disease progression (Ruth I. Connor, et al., J. Exp. Med. 1997, 185, 621). This finding is consistent with the recent finding that the presence of a CCR-2 mutant, CCR2-64I, is positively correlated with delayed onset of HIV in the human population (Michael W. Smith, et al., Science 1997, 277, 959). Although MCP-1 has not been implicated in these processes, it may be that MCP-1 antagonists that act via binding to CCR-2 may have beneficial therapeutic effects in delaying the disease progression to AIDS in HIV-infected patients.
Recently, a number of groups have described the development of small molecule antagonists of MCP-1 (reviewed in: Bharat K. Trivedi, et al, Ann. Reports Med. Chem. 2000, 35, 191). Workers at Teijen and Combichem reported the use of cyclic amines (A) as MCP-1 (Tatsuki Shiota, et al., WO 99/25686; Tatsuki Shiota, et al., WO 00/69815) and MIP-1α (Christine Tarby and Wilna Moree, WO 00/69820) antagonists. These compounds are distinguished from those of the present invention (I) by the requirement for the central cyclic amine grouping. 
A number of other groups have also described the development of small molecule antagonists of the MCP-1/CCR-2 interaction. To date, indolopiperidines (Ian T. Forbes, et al., Bioorg. Med. Chem. Lett. 2000, 10, 1803), spiropiperidines (Tara Mirzadegan, et al., J. Biol. Chem. 2000, 275, 25562), quaternary amines (Masanori Baba, et al., Proc. Natl. Acad. Sci. 1999, 96, 5698), 2-substituted indoles (Alan Faull and Jason Kettle, WO 00/46196; Andrew John Barker, et al., WO 99/07351; Andrew John Barker, et al., WO 99/07678), pyrazolone derivatives (Janak Khimchand Padia, et al., U.S. Pat. No. 6,011,052, 2000), 2-substituted benzimidazoles (David Thomas Connor, et al., WO 98/06703), N,N-dialkylhomopiperazines (T. Shiota, et al., WO 97/44329), bicyclic pyrroles (Andrew J. Barker, et al., WO 99/40913 and Andrew J. Barker, et al., WO 99/40914), and 5-aryl pentadienamides (K. G. Carson, et al., Cambridge Health Tech Institute Chemokine Symposium, McLean, Va., USA, 1999) have all been reported as MCP-1 antagonists. The foregoing reference compounds are readily distinguished structurally from the present invention by virtue of substantial differences in the terminal functionality, the attachment functionality, or the core functionality. The prior art does not disclose nor suggest the unique combination of structural fragments that embody in the novel compounds described herein. Furthermore, the prior art does not disclose or suggest that the compounds of the present invention would be antagonists of MCP-1.
It should be noted that CCR-2 is also the receptor for the chemokines MCP-2, MCP-3, MCP-4, and MCP-5 (Luster, New Eng. J. Med. 1998, 338, 436-445). Since it is presumed that the new compounds of formula (I) described herein antagonize MCP-1 by binding to the CCR-2 receptor, it may be that these compounds of formula (I) are also effective antagonists of the actions of MCP-2, MCP-3, MCP-4, and MCP-5 that are mediated by CCR-2. Accordingly, when reference is made herein to “antagonism of MCP-1,” it is to be assumed that this is equivalent to “antagonism of chemokine stimulation of CCR-2.”